Getting targetFeedReadOnly error in simple YouTube search query

Question

Hello im beginner in the YT api , i trying to query YT api with search query
from c++ http client with post request
the request string looks like this :

 http://gdata.youtube.com/feeds/api/videos?max-results=10&orderby=published&q=Skinny%20puppy&start-index=1&v=2

no headers and no autontication has bean made and the error im
getting :
 <errors xmlns='http://schemas.google.com/g/2005'&gt;
<error>
<domain>GData</domain>
<code>targetFeedReadOnly</code>
<internalReason>Target feed is read-only</internalReason>
</error>
</errors>

why is that , im doing what it said in the documention.